The present invention relates to a method and a device for the automatic computer-aided design of a supply network for a microelectronic circuit.
In the case of a power supply of a microelectronic circuit, designed in the Full Custom Design, for example, with a very current-intensive data path circuit, it is necessary to use effective wiring that supplies the circuit with current or power in a very stable manner. Because of the very high frequencies with which data path circuits of this type are operated, power consumption is very high, especially in CMOS circuits. In order to keep the supply voltage of the circuit stable, the wiring is effected via a supply network of metal layers. This supply network is generated with a physical density, i.e. a metal density, which is dependent on the power consumption and on design rules. Use of the supply network generated, which is also called a power grid, with the circuit to be supplied, takes place by means of vias which are arranged precisely where supply lines of the circuit intersect with the supply network. In the process, a high density of the vias leads to an efficient power supply, as a resistance from a voltage source to the circuit and therefore also a drop in voltage from the voltage source to the circuit is thereby kept low.
According to the prior art, the supply network is generated manually in a very time-consuming process or method by a layouter. In this instance, if there is a change to the layout of the circuit, the supply network for this circuit has to be changed with high outlay or occasionally even has to be completely reproduced. According to the conventional method, the supply network is designed in that individual modules are created which are joined together manually in such a way that a complete network is produced covering the entire layout of the circuit. In this instance, deviations from a regular structure of the supply network have to be generated manually in separate cells and inserted at the corresponding position.